Why not use a speaking name for the branch?

Right-clicking a group in SmartGit 19.1 there also is a "Add Group" menu item.

Since the beginning you can move repositories to groups using the context menu. Please also try SmartGit 19.1.

Ah, you are right. For the Create Tag dialog there is the completion. But independent of this, you can select from the combobox popup and then modify.

Please try Ctrl-Space.

The prefix, e.g. "fixup! " can be configured with the low-level property log.useCommitMessage.prefix.

Please take a look at https://www.syntevo.com/blog/?p=4751.

For what language?

One further clarification: what should happen if you paste some text containing tab characters?

For me it often happens that I need to amend different commits in a row. I now use "Use Message for Commit" and commit my changes (for multiple commits). If I have done all my commits, I use Interactive Rebase with one of the Auto-Squash options. I can't imagine a simpler work-flow. One always need to select the files to commit, select the commit's message to use.

Adding this to the Commit would make the already difficult Commit even more difficult to catch all border cases. So, for example, it is unexpected to get a conflict when committing, but this might happen with your suggestion 2 times - for the necessary rebase after the commit and for the auto-stash/apply/stash if there are local changes.